Introducing the Lotus Evora 414E Hybrid

The 80th International Geneva
Motor Show sees Lotus Engineering unveil the
Lotus Evora 414E Hybrid concept, a high
performance technology demonstrator with a
plug-in series hybrid drive system and new
technologies for enhanced driver involvement.

The Lotus Evora 414E Hybrid,
so-named because this latest
environmentally-focused technology demonstrator
from Lotus Engineering produces 414 PS (306 kW)
of power, promises breathtaking performance from
a highly efficient propulsion system. The
concept showcases new developments in plug-in,
range-extended electric propulsion, new
electronic technologies to enhance driver
involvement, the adaptability of the Lotus
Versatile Vehicle Architecture (VVA) that
underpins the Evora 414E Hybrid and a dramatic
new roof system and interior concept from Lotus
Design. Through all of these aspects it
ultimately demonstrates the exceptional ability
of Lotus Engineering to integrate and develop
advanced technologies for exciting, efficient,
high performance niche vehicles.

The range extended electric drive of the Evora
414E Hybrid consists of two electric motors
driving each of the rear wheels independently
via single speed geartrain, integrated into a
common transmission housing, thus enabling
torque vectoring for stability control of the
vehicle. Electrical power is stored in a lithium
polymer battery pack optimised for energy
density, efficiency and high power demand,
mounted in the centre of the vehicle for
stability and safety. Additional range is
provided by the Lotus Range Extender engine, an
optimised 1.2 litre, three-cylinder engine,
designed specifically for series hybrid vehicles.
The drivetrain is designed to combine
astonishing performance with efficient, low
emissions driving.

Driver involvement is enhanced by the
incorporation of HALOsonic Internal and External
Electronic Sound Synthesis technologies from
Lotus and Harman International, which provide
sound contouring within the cabin and improve
pedestrian safety outside the vehicle.
Integrated with the HALOsonic technology, the
Evora 414E Hybrid also showcases a brand new
technology from Lotus Engineering, a sports mode
that simulates a 7 speed, paddle shift
transmission that combines exceptional driver
involvement for a hybrid sports car and
optimised energy recuperation.

The Evora 414E Hybrid has been designed to
highlight Lotus’ innovative electric and hybrid
vehicle technology without distracting from the
pure sportscar character of the Evora. The
solution is innovative, instantly recognizable,
beautiful and sporty. It demonstrates Lotus DNA.

Dr Robert Hentschel, Director of Lotus
Engineering said: “Innovation has always been at
the heart of Lotus and is needed now more than
ever. The Evora 414E Hybrid is the perfect
demonstration of Lotus Engineering’s core
competencies: lightweight architectures,
efficient performance, electrical and
electronics integration and driving dynamics.
The technology demonstrator represents an
encapsulation of the advanced technologies that
Lotus Engineering continues to develop to
overcome the current environmental challenges
facing the automotive industry and showcases the
future direction that the sector is taking and
why Lotus Engineering is perfectly placed to
lead the technological development in this area.”

The Drivetrain

For the Lotus Evora 414E Hybrid, Lotus
Engineering has developed a highly efficient,
high performance drivetrain system consisting of
twin motors each limited to providing 152 kW
(207 PS/204 hp) of power and 400 Nm (295 lbft)
of torque to each wheel via independent, single
speed, reduction transmissions integrated into a
single housing, enabling torque vectoring
dynamic control of the vehicle.

The vehicle energy storage system is made up of
the latest Lithium Polymer battery chemistry
providing 17 kWH energy storage capacity. The
battery pack is optimised for energy density,
efficiency and high power demand, with over 100
kW discharge capability.

The Lotus Range Extender engine provides 35 kW
(48 PS/47 hp) of power at 3,500 rpm via the
integrated electrical generator and features an
innovative architecture comprising an aluminium
monoblock construction, integrating the cylinder
block, cylinder head and exhaust manifold in one
casting. This results in reduced engine mass,
assembly costs, package size and improved
emissions and engine durability. The engine uses
an optimised two-valve, port-fuel injection
combustion system to reduce cost and mass and
can be operated on alcohol-based fuels and/or
gasoline. The generator converts mechanical
energy to electrical energy to replenish the
battery pack charge and provides additional
vehicle range in a small light weight package.
The generator is also used as a motor to start
the range extender engine. The low mass of the
range extender unit (85 kg) and compact package
makes it ideal for the series hybrid drivetrain
in the Evora 414E Hybird.

All the operation and management of the range
extender engine, the power management of the
batteries and motor control are controlled by
Lotus’ electronic control units and software
systems. Full energy management of all the
operating systems is the key to maximising
performance and operation while minimising
energy consumption and CO2 emissions.

For everyday commuting journeys, up to 35 miles
can be travelled using battery power. The
battery can be charged overnight using a
conventional domestic mains supply through a
socket concealed by the rear number plate. This
permits the vehicle to operate with zero
tailpipe emissions. For longer journeys,
exceeding the battery capacity, the highly
efficient range extender engine is used as a
generator to supply the motor with electrical
power and top up the battery.

Lotus has used its own vehicle simulation tools
to determine the size, capacity, power and
performance of all the components in the
drivetrain system to optimise the system
operation. Overall this is far more energy
efficient, weight efficient and cost effective
than fitting the vehicle with a larger and more
expensive battery, which for the majority of
short journeys is a redundant weight, which
increases energy requirements. With regard to
the total lifetime CO2 emissions of the vehicle,
including the energy required to manufacture and
run it, the range extender solution has a lower
overall CO2 footprint than a fully electric car
of comparable performance and operating range
running with a larger battery.

The Package

The Lotus Evora 414E Hybrid structure is the
same award-winning, versatile vehicle
architecture used on the Lotus Evora. The low
volume architecture was designed with the upmost
flexibility in mind. The Evora 414E Hybrid is a
perfect example of how to integrate a compact
packaged drivetrain, with excellent performance
and range, while using this underpinning. The
complete chassis has remained unchanged from the
Evora which maintains the structural integrity
and strength performance of the original car.

The structure progresses the Lotus ‘bonded and
riveted’ technology with new and unique
extrusions and folded panels, whilst providing
production build modularity and lower cost
repairs. The chassis has been designed for
scalability so that it can be extended in width,
length and height. The strength and stiffness of
the low volume VVA chassis can be modified cost
effectively by varying the wall thickness of the
extrusions, without altering the exterior
dimensions. The ability to lengthen or shorten
extrusions with the option to tailor the chassis
stiffness vastly increases the number of
vehicles that can be developed from this vehicle
architecture.

Driving Dynamics

The Lotus Evora 414E Hybrid offers exhilarating,
all-round dynamic performance and takes
advantage of Lotus developed torque vectoring
dynamics. Torque vectoring, which is the
capacity to generate different torques at each
of the driving wheels, is particularly suited to
electric vehicles and significantly reduces the
conflict between stability and response.

A key benefit of separate motors to drive each
rear wheel individually is that this facilitates
a much higher level of vehicle dynamics control.
Driving the wheels with different levels of
torque can not only generate all the
capabilities of a conventional ESP system using
energy regeneration as opposed to brake
application, but it can also actively drive each
wheel forward at different rates, producing a
turning moment at the rear of the vehicle in
addition to the steering input.

This can be used to enhance low speed
manoeuvrability and ease of parking but can also
be used to produce a much greater level of
straight line high speed stability.
Incorporating lateral sensors the system also
provides stability control capabilities and
levels of steering response normally only
associated with heavy and expensive rear steer
systems. This can provide automatic correction
of both understeer and oversteer characteristics.
In addition, the standard method to provide high
speed stability of designing the rear wheels to
toe-in is not required as the torque vectoring
system automatically provides this stability
control, with toe-in increasing rolling
resistance, lowering fuel economy and increasing
tyre wear. Lotus‘ long history of active
suspension control provides the core capability
to develop this technology and provides
extraordinary driving pleasure on the Evora 414E
Hybrid.

Driver Interaction

The Evora 414E Hybrid provides less of a
psychological step change for people familiar
with high performance cars compared to other
electric and hybrid sports cars. The car has a
simulated paddle shift gear change offering
ultra quick gear changes reminiscent of a dual
clutch transmission, while actually single
speed. This enhances the driver interaction with
the vehicle and provides a driving experience
similar to current internal combustion engine
high performance sports cars. The Evora 414E
Hybrid uses a column mounted paddle shift to
simulate the gear change and a synthesised
engine sound changes frequency with virtual gear
selection. The drive torque is also modulated to
simulate a physical feeling of a gearshift jolt.

The virtual gearshift simulation, like a
conventional gearbox, is used to change the
driving characteristics and response of the
vehicle. The most significant aspect that this
offers the driver is the ability to control the
vehicle deceleration by simulating engine
braking through a virtual downshift in gears.
Unlike true engine braking, the Lotus system
does not dissipate the energy of the moving
vehicle through internal engine friction but
uses the electric motors to regenerate the
energy back into the battery. While many
electric and hybrid vehicles provide engine
braking, this is generally at a fixed rate or
preselected rate. In some driving situations
this can either be too aggressive, slowing the
vehicle unnecessarily, or too light, requiring
additional braking application. The Lotus system
effectively allows the driver to select the
appropriate level of regeneration by simulating
stepping down by one, two or even three gears.
The simulation of engine braking through both
the gear noise change and the retardation of the
vehicle is fully intuitive to a driver familiar
with a conventional gearbox. The simulated
gearchange capability can be selected for
greater driving involvement or switched off for
more relaxed driving.

The Evora 414E Hybrid uses the Lotus Engineering
and Harman International developed HALOsonic
suite of noise solutions. The first of which is
Electronic Sound Synthesis. This generates
engine sounds inside the vehicle through the
audio system where it provides an exciting
sports sound in line with the brand and nature
of the vehicle together with a high level of
driver feedback in an intuitive manner. In
addition, it also generates sound on the outside
of the vehicle through speakers mounted at the
front and rear to provide a warning to increase
pedestrian safety, which is especially important
for electric and hybrid vehicles which can be
difficult to hear at slower speeds.

There are four driver selectable engine sounds
currently on the vehicle, two of which have been
designed to have characteristics of a
multi-cylinder conventional V6 and V12 engine.
There is also a futuristic sound and a
combination of a conventional engine and a
futuristic sound, enhancing the brand identity
of the vehicle as a step forward in electric
vehicle design.

The addition of this Lotus patented simulated
gearshift concept not only provides for an
exciting and involving driving experience that
customers would expect from a Lotus, but also
enhances the driver’s control of the vehicle
while providing the capability for more
efficient operation through a greater use of
energy regeneration.

The Design

The distinctive colour scheme and ‘floating’
roof have been carefully designed to accent the
cars electric vehicle technology whilst
complementing the iconic lines of the Evora.

Copper, a colour often associated with
electrical systems, has been chosen for the
car’s exterior and interior. A contemporary
satin finish paint is complemented by electrical
circuit inspired graphics that highlight the
car’s key feature lines and the unique glazed
roof panel. The newly extended glazed zone
integrates seamlessly with the existing forms of
the Evora whilst showcasing the key components
behind the hybrid and electric vehicle
technology.

The signature copper theme is consistently
carried throughout the car from the dramatic
seat stripes and instrument panel inserts to the
copper callipers that nestle behind the carbon
grey forged wheels. Inside the cabin a sense of
quality and richness has been created by
carefully juxtaposing the different tactile
qualities intrinsic to leather, Alcantara and
metal.